THINNING HISTORY OF THE FOUNDATION-THIEL TROUGH ICE STREAM: A KEY CONTROL ON DEGLACIATION OF THE WEST ANTARCTIC ICE SHEET, WEDDELL SEA EMBAYMENT
Lead Research Organisation:
Durham University
Department Name: Geography
Abstract
The Antarctic ice sheet is the largest on earth and any instability is likely to dominate global sea level change. We therefore require models of the ice sheet to make more reliable and robust predictions of future change. One problem in meeting this challenge is the lack of past data on deglaciation with which to initialize and calibrate the models. This problem has been particularly acute in the Weddell Sea embayment and in particular its eastern part where the Foundation - Thiel Trough has been a principal drainage route for the West Antarctic Ice Sheet (WAIS), and its southern extension may be a potential location for future instability. We propose here an integrated field and modelling study that will exploit the opportunity of several emerging field datasets from a range of different disciplines, collect fresh data from a crucial location, and investigate past and future deglaciation using sophisticated ice sheet models. To understand the history of ice thinning and retreat along the trough we will adopt a dipstick approach to survey the Foundation Ice Stream, an upstream extension of the ice stream that occupied the trough during the last ice age. We will determine the thinning history of this Foundation-Thiel Trough Ice Stream from geomorphology and exposure age dating: techniques that have been used effectively to provide insight into ice sheet history in other regions of Antarctica. We will apply a 3D model - incorporating significant recent theoretical advances - to the whole of the WAIS in order to understand the forcing mechanisms for the ice stream history we measure. We will go on to use this model to predict the likely future stability of the WAIS in terms of both long-term trajectory and any response to climate change scenarios, and in particular whether it will retreat further along the Foundation-Thiel Trough.
Organisations
Publications
Bentley M
(2014)
A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum
in Quaternary Science Reviews
Bentley M
(2017)
Deglacial history of the Pensacola Mountains, Antarctica from glacial geomorphology and cosmogenic nuclide surface exposure dating
in Quaternary Science Reviews
Bradley S
(2015)
Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice-sheet readvance
in Earth and Planetary Science Letters
Chang M
(2015)
The surficial and subglacial geomorphology of western Dronning Maud Land, Antarctica
in Journal of Maps
Fogwill C
(2012)
Do blue-ice moraines in the Heritage Range show the West Antarctic ice sheet survived the last interglacial?
in Palaeogeography, Palaeoclimatology, Palaeoecology
Hillenbrand C
(2014)
Reconstruction of changes in the Weddell Sea sector of the Antarctic Ice Sheet since the Last Glacial Maximum
in Quaternary Science Reviews
Hindmarsh, R.C.A.
(2020)
Radars and Ice Cores Reveal Styles of Retreat of Greenland and Antarctic Ice Sheets
in ECO SI
Hodgson D
(2012)
Glacial geomorphology and cosmogenic 10 Be and 26 Al exposure ages in the northern Dufek Massif, Weddell Sea embayment, Antarctica
in Antarctic Science
Jamieson S
(2014)
The glacial geomorphology of the Antarctic ice sheet bed
in Antarctic Science
Johnson JS
(2014)
Rapid thinning of Pine Island Glacier in the early Holocene.
in Science (New York, N.Y.)
Jones R
(2019)
Impact of glacial isostatic adjustment on cosmogenic surface-exposure dating
in Quaternary Science Reviews
Jones R
(2019)
iceTEA: Tools for plotting and analysing cosmogenic-nuclide surface-exposure data from former ice margins
in Quaternary Geochronology
King MA
(2012)
Lower satellite-gravimetry estimates of Antarctic sea-level contribution.
in Nature
Lee JE
(2020)
An 83,000 year old ice core from Roosevelt Island, Ross Sea, Antarctica
in Climate of the Past
Matsuoka K
(2015)
Antarctic ice rises and rumples: Their properties and significance for ice-sheet dynamics and evolution
in Earth-Science Reviews
Paxman G
(2019)
Subglacial Geology and Geomorphology of the Pensacola-Pole Basin, East Antarctica
in Geochemistry, Geophysics, Geosystems
Ross N
(2011)
Holocene stability of the Amundsen-Weddell ice divide, West Antarctica
in Geology
Shepherd A
(2012)
A reconciled estimate of ice-sheet mass balance.
in Science (New York, N.Y.)
Siegert M
(2019)
Major Ice Sheet Change in the Weddell Sea Sector of West Antarctica Over the Last 5,000 Years
in Reviews of Geophysics
Small D
(2019)
Antarctic ice sheet palaeo-thinning rates from vertical transects of cosmogenic exposure ages
in Quaternary Science Reviews
Whitehouse P
(2017)
Controls on Last Glacial Maximum ice extent in the Weddell Sea embayment, Antarctica
in Journal of Geophysical Research: Earth Surface
Wolstencroft M
(2015)
Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea
in Geophysical Journal International
| Description | First deglacial history of the Foundation-Thiel Trough Ice Stream (FTTIS) Modelling shows that the FTTIS only has a small number of stable grounding line locations. This has implications for its past extent and stability. The FTTIS probably did not reach the continental shelf edge, and if it did it was only thin ice and for a short period of time. |
| Exploitation Route | Helps understand stability of ice in Weddell Sea embayment |
| Sectors | Environment |
| Title | Questions about ice dynamics formulated on the basis of newly acquired data |
| Description | The large group of earth scientists involved in investigating the palaeo-Antarctic Ice-Sheet (p-AIS) and palaeo-British-Irish Ice-Sheet (p-BIIS) has quite naturally led them to think about ice dynamical explanations for their observations. Nearly all of their conjectures and questions are well thought-through, which ultimately create questions for ice dynamicists and modellers to answer. We are improving and amending models to focus on these questions. |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2015 |
| Provided To Others? | Yes |
| Impact | There are several different groups working on the p-AIS and p-BIIS, all aiming to make use of the new data. These groups talk with each other, but are all interested in different aspects of the behaviour of the ice-sheet. |
| Title | Velocity profiles - Adelaide, Berkner, Fletcher, Roosevelt |
| Description | Vertical velocity data from within a few kilometres of four ice divides sitting within ice rises. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2014 |
| Provided To Others? | Yes |
| Impact | Provides data that can be used to invert for (i) ice rheology; and (ii) the formation date of the ice-rise. |
| Title | Velocity profiles from ice-rises. - Korff, Henry, Skytrain, Fowler, Fletcher |
| Description | Vertical velocity profiles can be measured with two accurately co-located radar surveys separated by a suitable period of time - in these cases, one year. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | These velocity profiles can be used with radar surveys of sub-surface structure to date the formation time of the ice-rises. The ice-rises are about 100 km by 30 km in horizontal dimension, up to 600 m thick. |
| Title | BASISM - the BAS Ice Sheet Model |
| Description | BASISM has been developed over the past fifteen years, and has achieved successes in formal model intercomparison projects (MIPs), as well as being used to settle some long-standing problems. |
| Type Of Technology | Software |
| Year Produced | 2013 |
| Impact | This software (and its brethren) have been used in MIPs to validate theoretical advances in grounding-line motion/stability and ice-stream formation. |
| Description | Celebrating Charlie Raymond's 80th Birthday |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Charlie Raymond was a highly successful glaciologist who influenced a great number and variety of scientists. My field work post-2000 CE was organised around his ideas regarding ice flow near ice divides; these ideas are called the 'Raymond Effect' which lead to anticlines called 'Raymond Arches', which are detected by ice-penetrating radar. The event attracted a wide variety of scientists. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Modelling panel for BRITICE, for groups both internal and external to the main BRITICE project |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | The new data acquired by BRITICE from the North, Norwegian and Celtic Seas shows very clearly that the British-Irish Ice Sheet (BIIS) was a marine ice-sheet. The stability of such ice sheets is a major concern, since Antarctica is a marine ice-sheet and its observed retreat threatens to raise global sea-level by between 0.5m and 2m by 2100 CE. The quantity of new data points means the the BIIS is the most well-described marine ice-sheet, and already these data are illuminating issues of marine ice-sheet stability. |
| Year(s) Of Engagement Activity | 2014,2015,2016,2017,2018 |